Does the ``??`` operator use shortcircuiting?

Question

Does the `??` operator in C# use shortcircuiting when evaluating? var result = myObject ?? ExpressionWithSideEffects(); When ``myObject`` is non-null, the result of ``ExpressionWithSideEffects()`` is not used, but will ``ExpressionWithSideEffects()`` be skipped completely?

Answer 1

Yes, the ?? operator in C# uses short-circuit evaluation. In an expression like var result = myObject ?? ExpressionWithSideEffects();, the right hand side is evaluated only if myObject is null. If myObject already contains a non-null value, C# immediately returns that value and completely skips ExpressionWithSideEffects(). This means the method is not called at all, and any side effects it may contain will never occur. Therefore, when myObject is non-null, ExpressionWithSideEffects(0 is not just ignored for the result, it is fully bypassed.

Answer 2

Yes, the rest of the expression after the ?? operator will not run at all if the left-hand argument is not null.